Resilient top roll and nippers for drawing frames of spinning machines



Oct. 31, 1961 A. R. BETT 0 3,006,037

RESILIENT TOP ROLL AND NI RS FOR DRAWING FRAMES OF P NNING MACHINESFiled 11 21, 1958 United States Patent RESEIENT TOP ROLL AND NIPPERS FORDRAW- ING FRAMES 0F sPlNNlNG MACHINES Aroldo Roberto Bettolo, Novara,Italy, assignor to S.p.A. Oificina Meccanica SantAndrea Novara, Novara,Italy Filed Apr. 21, 1958, Ser. No. 729,604 Claims priority, applicationItaly Apr. 29, 1957 4 Claims. (Cl. 19142) This invention relates totextile fibre drafting rolls.

The use of resilient textile fibre drafting rolls, more particularly toprolls, in drawing frames for a spinning machine, has been repeatedlyproposed; however, none of the numerous constructions could besuccessfully employed in practice.

It has been proposed to provide top rolls with a resilient covering,i.e. a cylindrical skirt of relatively large thickness and elasticity.Since the guiding of the fibres, particularly the lateral fibres, of asliver was found to be insufficient, clearances were left within therelatively thick skirts or resilient material, of a form such as toremain unaltered under the action of weighting in respect of form andsize in an axial direction.

According to a further proposal, a resilient intermediate body providedwith a leather or rubber coating was secured to the roll core. Thisintermediate resilent body could comprise, according to this furtherproposal, a circular brush of thin wire or a brush fitted with animal orvegetable bristles. Finally, it was further proposed to make up theintermediate body of spring plates in the form of barrel staves.

It is further known to provide resilient top rolls with lateral ringsadapted to absorb the weighting required for safely producing therequired rotational cooperation with driven bottom rolls so that thepressure exerted by the resilient body on the fibres of a sliver beingpassed through the nip of a pair of cooperating rolls in a draw ingframe is not affected by weighting. In known top rolls of this kind, theresilient body is securely positioned between the lateral rings. Theresilient material of the body clamped between the lateral rings, sinceit cannot yield axially under weighting, is undesirably crushed. Thisresults constantly in an uneven distribution of the nipping pressureand, as a rule, in an insnflicient nipping of the edge fibres of asliver. The change in passage of the sliver, of which the provision isdesirable in all drawing frames, cannot therefore be employed when toprolls of the last described type are used on account of the irregulardistribution of pressure. On the other hand, if the sliver alwaystravels at the same point, the top roll of the feed roll or deliveryroll becomes after a short period of use useless.

Finally, it has been proposed to use, instead of lateral rings, a hollowresilient skirt provided at both ends with protecting plates made of thesame material as the skirt. However, experiments carried out withresilient rolls of this type, disclosed that the distribution of thenipping pressure becomes still less even.

In other known top rolls, a resilient sleeve of cylindrical shape isfitted on the roll core which is provided with lateral rings. In thiscase the sleeve bears on the rings, leaving a clearance between the rollcore and sleeve. In this proposed embodiment, weighting does not alterthe form of the sleeve.

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The resilient nipping is but small and almost always insufficient.Moreover, the nipping pressure is heavier in the middle than at thesides of a sliver being passed through the nip.

It is an object of the present invention to overcome imperfections anddrawbacks ascertained in practical use of resilient top rolls knownheretofore, and to provide the roll with a body made of resilientmaterial capable of freely expanding under the action of weighting in anaxial direction, so that a uniform nipping pressure can be applied on toa sliver throughout the width of the nip.

According to the present invention there is provided a textile fibredrafting roll comprising a core having a pair of rings or ribs providedaround, and axially spaced from one another along, the core, and asleeve of resilient material mounted "around the core. The sleeve has apart extending over the rings, the inner diameter of this part is largerthan the outer diameter of the rings or ribs, so as to be normally outof contact with the periphery of the rings or ribs. The sleeve is suchthat, when the roll is brought into rolling contact with acounter-pressure device for the pressing therebetween of a sliver oftextile fibres, the rings or ribs are able to engage the sleeve in thearea of contact and the portion of the sleeve interjacent the rings orribs is able to cooperate with the counter-pressure device in therolling and pressing of the sliver.

For a better understanding of the invention and to show how the same maybe carried into effect, reference will now be made to the accompanyingdrawings in which:

FIGURE 1 is an elevation view illustrating a resilient top rollassociated with a fluted bottom cylinder, a part of the top roll beingshown in section,

FIGURE la is a cross-sectional View of FIGURE 1,

FIGURE 1b is a similar view to FIGURE 1, the arrangement comprising atoproll of modified construction,

FIGURE 2 is a similar view to FIGURE 1, the arrangement comprising amodified cooperating bottom roll device with an elastic belt.

FIGURE 2a is a cross-sectional view of FIGURE 2,

FIGURE 3 is a similar view to FIGURE 1, the arrangement comprising afurther modified bottom roll, similar to the top roll,

FIGURE 3a is a cross-sectional view of FIGURE 3,

FIGURE 4 is a view similar to FIGURE 1, the arrangement comprising astill further modified cooperating bottom roll device, and

FIGURE 4a is a cross-sectional view of FIGURE 4;

In the drawings, corresponding parts of the figures have been given thesame reference numerals.

Referring to FIGURES 1 and 1a, the top roll comprises a core 1 providedwith lateral rings or collars 2 and 2. A cylindrical sleeve 3 made ofresilient material, as for example, oil-proof synthetic rubber, isfitted on the core, the inner diameter of the sleeve being larger thanthe outer diameter of the collars. The end portions of the sleeve 3 areinturned 4 and 4' and rest at their ends against the outside of thecollars 2 and 2'. The sleeve 3 thus envelops the collars. When the topand bottom rolls are disengaged, a circumferential clearance 5 is leftbetween the core 2 and the sleeve 3, but upon the top roll being loadedto bear against a fluted bottom roll or shaft 6, the clearance 5 isreduced in the region of rollto an extent such that the sleeve ispressedagainst the periphery of the collars 2 and 2'.

When the sliver f of textile fibres is passed between the nip of thecooperating top and bottom rolls, the thickness of the sliver causes themiddle portion of the sleeve interjacent the collars 2 and 2' to yieldfarther radially inwardly towards the core 2 while the rings pinch theadjacent portions of the sleeve against the bottom roll 6. The pinchingaction of the collars thus prevents parts of the sleeve being drawnaxially past the collarstowards thecenter by the tension induced'inthemiddle portion of the sleeve bythe sliver f. The yielding movement ofthe middle portion of the sleeve towards the core is therefore dependenton the ability of the sleeve material to stretch. The nipping pressureexerted by the middle portion ofv the sleeve can also, therefore, bepredetermined and is chiefly dependent on the hardness, resiliency, anddiameter of the sleeve. The pressure exerted on the sliver by the middleportion, which. in efiect constitutes the working width of the toproller, is further uniform between the rolls.

Once the sleeve is pinched between the rings and bot tom-roll, increasedpressure on the top-roller against the bottom roll cannot affect thenipping pressure of the sleeve on-the sliver.

Asshown in FIGURE 1a, the middle portion of the sleeve yields inaccordance with the curvature of the bottom rollso as-partly to encirclethe latter over the arc a-b. The yielding of the middle portion of thesleeve towards the axis of the core being of course greatest where thesleeve'intersects the planecontaining the axes of the top and bottomrolls. The-nip betweenthe top and'bottom rolls istherefore constitutedby a curved area, which affords amore efiicient guide for the fibres ofthe sliver f therebyincreasing the drawing efficiencyof the-drawingmechanism. Uniformity of nipping pressure throughout theoperative widthof thenip can be easily ascertained andmeasured by the resistanceopposed to a thin thread or athin strip in various parts of the nipduring drawing. Generally, the lateral fibres of a sliver are guided ina particularly efiicient manner through the illustrated device.

In FIGURE 1b, the inturned edge portions of the sleeve 3 of FIGURE 1have been replaced by annuli 7 and 7' made of the same material as thesleeve or made of soft resilient material, for example sponge rubber, orconsist ing-of resilient tubular rings. The annuli 7 -and-7 may eitherbe. firmly secured-to-the sleeve or may consist of movable rings. In thelatter case, it is; desirable to secure them against axial displacement;

For most practical requirements, the arrangement shown in FIGURES 1 and1a and the arrangementshown in FIGURE 1b, which arrangements have'aplain bottom roller or shaft, will-be sufficient.

In FIGURES 2 and 2a, the top roll is similar to the top roll ofFIGURE 1. The bottom roll 6, however, is formed with a portion 6' ofreduced diameter beneath the middle portion of the sleeve 3, whichreduced portion serves to accommodate and guide a belt 8-made of softand resilient material such as sponge'rubber or the like. The outersurface of the belt may be covered with a thin s ip of rubber, leatheror the like. The radial walls of the portion 6' also serve to improvethe guiding and control'of the fibres of a sliver passed through thenip.-

In FIGURES 3 and 3a, the bottom roll 6" has lateral rings 2" and aresilient. sleeve having inturned end portions so thatv the top andbottom rolls have similar construction, features. This arrangementconsiderably enlarges the nipping surface (see FIGURE 3a) as comparedwith the nipping surface of: either FIGURE 1a or FIG- URE 2a.

It:will of course be understood that the-bottom roll may, haveconstruction, featuressimilar. to those of the top roll shown in FIGURE1b.

FIGURES 4 and 4a illustrate a further alternative arrangementcomprisinga top rollof similar construction to the top roll of FIGURE 1. The toproll 1 co-operates with a counter-pressure device comprising a bottomroll 6, a belt reversing or guide bar 10 located forwardly of the roll 6in the direction of movement of the sliver, and a belt 9 adapted totravel over the roll 6 and the bar 10. The top roll 1 is arranged tobear principally on the belt 9 between the roll 6 and the bar 19 therebyobtaining greater resilience. Such an arrangement affords a particularlylarge nipping surface as shown in FIGURE 4a. This arrangement. moreoveradvantageously reduces the nip space between the draft rolls and controlrolls.

In 'anarrangement of this kind, it will be appreciated that the positionof the top roll andof its bottom roll or cooperatingdevice may beinterchanged.

What I claim is:

1. In a drafting apparatus for drafting sliver and the like, incombination, a pair of elongated members at least one of which comprisesa roll, said members having in operation relatively moving peripheralsurfaces. c0- operative in forming in operation a drafting zone betweenthem, said members being disposed parallel and radially disposedrelative to one another, said roll having a core provided with axiallyspaced collars fixed thereon for rotation therewith, a resilient sleevedisposed extending axially over said core for rotation with saidrollwith opposite ends disposed axially outwardly of the collars, saidsleeve having an inner diameter greater than the diameter of saidcollars and portions thereof radially adjacent said collars radiallyspaced from said collars, and in operation said collars'being disposedrelative the other of said elongated members in position for bearing oncorresponding portions of the sleeveradially adjacent thereof andcausing said portions to bear on said other member thereby defining thewidth of the drafting zone along an axial length of the membersintermediate the collars.

2. Ina drafting apparatus for drafting sliver and the like according toclaim 1, in which said members include a driven apron cooperative withsaid sleeve on said roll in defining the drafting zone.

3; In a drafting apparatus for drafting sliver and the like; incombination, a pair of elongated members at least one of which comprisesa roll, said members having in operation relatively moving peripheralsurfaces cooperativein forming in operation a drafting zone between 1'them, said members being disposed parallel and radially disposedrelative to one another, said roll having a core provided with axiallyspaced collars fixed thereon for I ing on corresponding portions of thesleeve radially adjacent thereof and causing said portions to bear onsaid other member thereby defining the width of the drafting zone alongan axiallength of'the members intermediate the collars, and a travelingbelt traveling over said other member between it and said roll along thezone intermediate thecollars of said roll.

4. In a drafting apparatus for drafting sliver and the like, incombination, a pair of rolls having in operation relatively movingperipheral, surfaces cooperative in forming in operation a drafting zonebetween them, said rolls being disposed parallel and radially disposedrelative to one another, one of said rolls having a core provided withaxially spaced collars fixed thereon for rotation therewith, a resilientsleeve disposed extending axially over said-core with opposite endsdisposed axially outwardly of the collars, said sleeve having an innerdiameter greater than the diameter of said collars and portions thereofradially adjacent said collars radially spaced from said collars, and inoperation said collars being disposed relative the other of said rollsin position for bearing on corresponding portions of the sleeveradial-1y adjacent thereof and causing said portions to bear on saidother roll thereby defining the Width of the drafting zone along anaxial length of the members intermediate the collars.

References Cited in the file of this patent UNITED STATES PATENTSPfiimlin June 9,

Pflimlin June 9,

FOREIGN PATENTS Great Britain July 10,

Great Britain Oct. 5,

Great Britain May 11,

France May 26,

